With its excessive plotting, heavy-handed use of London establishing shots and ponderous air of villainy, “All Things to All Men” could easily be dismissed as yet another minnow pulled from the overfished pond of British crime fiction. Nevertheless, the film proves intermittently watchable thanks to a moody star turn from Rufus Sewell, leading a roster of better supporting thesps than the material warrants. Producer-turned-helmer George Isaac (“Kidulthood,” “Adulthood”) shows glimpses of promise, but “All Things” has appealed to only a few men and probably fewer women since its April 5 domestic bow, despite a wide, self-distributed release.

Sewell plays bent Scotland Yard detective Parker, a cop interested in busting criminals only insofar as they might be useful to his avaricious schemes. Parker’s main aim is to build up the private retirement fund jointly held with his almost-as-corrupt partner, Sands (Terence Maynard). With newbie Dixon (Leo Gregory) in tow, Parker and Sands bust high-on-his-own-supply cocaine dealer Mark Corso (Pierre Mascolo, also one of the pic’s producers), the son of kingpin Joseph Corso (Gabriel Byrne), locally known as “the Merchant.”

With Mark in custody, Parker and Co. apply pressure to the Merchant to hire master thief Riley (Toby Stephens, dull as sawdust) to heist bonds from a London skyscraper using helicopters, which at least provides an excuse for some twinkly aerial nocturnes. But soon everyone seems to be double-crossing everyone else, a complicated scheme that requires the involvement of half a dozen other ill-defined characters, including the lone woman of note, a gangster’s grieving widow (Elsa Pataky, showing little enthusiasm in a skimpily written role). Indeed, most of the actors are largely phoning it in here apart from Sewell, and although the assembled talents elevate the film a bit, few are likely to include it in their future showreels.

With its dense array of alliances and betrayals, Isaac’s script can’t be faulted for lack of ambition, and it’s admirably willing to be oblique and sparing with its reveals. Still, even the most seasoned thiller aficionado with a working knowledge of Cockney-speak might struggle to work out what the hell is going on.

Clearly, the writer-director’s true talent, gleaned from his background as a producer, is in making sure the money is there onscreen: The budget was allegedly £3 million ($4.6 million), but it looks considerably more expensive, given the abundant use of locations in a city where street shooting is seldom easy. London auds will also appreciate that the characters’ movements from one locale to another make sense geographically (that’s more than can be said for Byrne’s accent, which ambles haphazardly from London’s Bow neighborhood to the Bronx to Dublin’s north side).

The credits fulsomely thank the staff at the well-known British hairdressing chain Toni & Guy, which is also run by exec producer Tony Mascolo, the father of producer-thesp Pierre. This may not account for the plot’s melodramatic emphasis on the fractious relationships between fathers and sons, but it almost certainly accounts for why everyone looks so tonsorially sleek.